Substantial attention has been paid to the creation of composite materials with unique properties. Included in this class of materials are materials with improved viscoelastic character, varying densities, varying surface characteristics and other properties which may be used to construct a composition with improved properties. Composite materials have been made in the past by combining generally two dissimilar components to obtain beneficial properties from both components. A true composite is unique because the interaction and engineered combination of the components provides the best properties and characteristics from both components.
Many types of composite materials are known. Generally, the art recognizes that combining metals of certain types and proportions to form an alloy that provides unique properties in the metal/metal alloy materials with different properties than the metals alone. Metal/ceramic composites have been made typically involving combining metal powder or fiber with clay materials that can be sintered into a metal/ceramic composite.
Combining typically a thermoplastic or a thermosetting polymer phase with a reinforcing powder or fiber produces a range of filled materials and, under the correct processing conditions, can form a true polymer composite. In contrast, a filled polymer, with the additive as filler, cannot display composite properties. A filler material typically is comprised of inorganic materials that act as either pigments or replacement for the polymer component. Fillers are often a substitution for a more expensive component in the composition. A vast variety of fiber-reinforced composites have been made typically to obtain fiber reinforcement properties used to modify only the mechanical properties of the polymer in a specific composite.
Polymer materials have been combined with cellulosic fiber to make extruded materials. However, such materials have not successfully been used in the form of a structural member that is a direct replacement for wood or other materials, such as aluminum and concrete, for temporary structures that are useful for military, commercial or building material applications. Such materials can be in the form of a decorative or structural material or member. Common extruded thermoplastic composite materials cannot provide thermal and structural properties similar to wood or other structural materials. These extruded materials fail to have sufficient modulus, compressive strength, and coefficient of thermal expansion that matches wood to produce a direct replacement material. Further, many prior art extruded composites must be milled after extrusion to a final useful shape. One class of composite, a polyvinyl chloride/wood flour material, poses the added problem that wood dust, which can accumulate during manufacture, tends to be explosive at certain concentrations of very fine, airborne, wood dust or powder.
Many of these materials containing polymer and particulate are admixtures of separate components and are not true composites. Admixtures are relatively easily separable into the constituent parts and, once separated, the component parts display the individual properties of the components. A true composite resists separation and displays enhanced and often different properties of the input materials whereas the individual input materials often do not display the enhanced properties. A true composite does not display the properties of the individual components but displays the unique character of the composite as a whole.